olmsted



2 Sheets-*Sheet l. J. OLMSTBD. MAGNBTO ELECTRIC MACHINE.

Patented July 12,1881.

Twan

(Model.) 2 Sheets-Sheet 2.. J. OLMSTED. MGNETO ELECTRIC MACHINE. No. 244,287. Patented July 12,1881.

attest/5 I Inventor.-

UNITED STATES PATENT OFFICE.

JOSEPH OLMSTED, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NElY YORK, N. Y.

MAGNETO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 244,287, dated July 12, 1881.

Application filed April 13, 1880. (Model.)

To all whom it may concern:

Beit known that I, JOSEPH OLMsrED, of the city and county of Providence, and State of Rhode Island, have invented certain new and useful Improvements in Magneto-Electric Machines; and I do hereby declare that the following specification, taken in connection with the accompanying drawings, forming a part of the same, is a full, clear, and exact de- Io scription thereof.

My invention relates to that portion of a magneto-electric machine known as the commutator,7 and its object is to produce results superior to those heretofore attained, by reducing the friction incident to the working of the device, by preventing the short-circuiting of the bobbins or coils, by providing a convenient means for adjusting the position ot' the commutator box with reference to the 2o change of polarity of the current induced in the bobbins, and by preserving a lubrication of the parts of the commutator during revolution. Y

. To these ends my improvements consist,

2 5 first, in the employment of a hollow cylindrical box or casin g, to which the outgoing wires of the machine are attached, and several series of movable fingers connected with the bobbins or coils and arranged within said box, so as to 3o come in contact with its interior surface by centrifugal force, for the purpose of maintaining a continuous current in one direction in the external circuit; secondly, in mounting the com mutator-box on a hub, whereby it may be made, by rotation, to assume any given position, for the purpose of adjustment, and be secured therein; thirdly, in the employment of adjustable supports for the free ends of the fingers; and, fourthly, in combining with the 4o conducting-segments of the commutator-box appropriate insulating material.

The commutator-box shown in the drawings is adapted for use with two or more pairs of bobbins, and with one or more magnets so l ing the number of conducting and insulating sections composing the commutator-box it 5o will be adapted to a greater number of changes of polarity.

Referring to the drawings, Figure l shows, in plan, my improvements embodied in a commutator, portions being cut away the better to show the parts. Fi g. 2 represents a verticalV transverse section of Fig. l on line .c x. Fig.

3 shows, in perspective, the mechanism within the commutator box or casing, and Fig. 4 represents, in perspective, a modification of such 6o internal mechanism. Fig. 5 is a cross sectional view through the commutator, illustrating in detail a modification of Fig. 3.

As shown in Figs. l and 2, A represents the base upon which the parts are mounted, and 6 5 A the standards secured thereto, in which the revolving portions of the device are journaled.

B B are the coils or bobbins-in this case four in number, although more or less may be used, if desired-which are mounted between 7o the disks or supports C on cores B. These disks are secured to the drivingshaft D, which is supplied with a pulley, (not shown in the drawings,) for the purpose ofgiving revolution to the bobbins. The magnets of the generator 7 5 (not shown in the drawings) are arranged in close proximity to one or both ends of the cores B. The said bobbins are arranged in pairs, one bobbin of each pair being diametrically opposite its fellow, and the interior 8o ends of their coils are connected. The exterior ends, b, of all coils are extended to the commutator, as shown in Fig. 1, and are attached to the rods E, respectively, as shown in Fig. 3. These rods E are mounted in the disks F, which are composed of gutta-percha, vulcanite, 0r other non-conducting material, and are secured to the shaft D, so as to revolve therewith.

Loosely mounted upon each rod E, as shown 9o in Figs. l, 2, and 3, is a series of metal fingers,

G, each independent of the other, the free ends of which will swing or move outward by centrifugal force during the revolution of the shaft D, and comein contact with the interior surface of the hollow cylindrical commutator box or casing H, which surrounds said fingers and is concentric with the shaft D. The box on a hub, K, secured to the standard A2. The

H is composed of two nearly semicircular metal sections, h h', each provided with a bin ding-screw for attaching the outgoing wires it" of the device, and of two strips, h2, of glass, mica, or an insulating material'possessin g similar characteristics. These several parts of the said box are arranged with reference to each other as shown in Fig. 2, their interior surfaces forming a perfect circle, and all are secured together so that the sections h h are insulated from each other. The material composing the insulating-strips h2 is an important factor in the working of the box H, since to obtain the best results it should be a substance not readily burned or charred, and which will wear evenly with the metal sections 7o h. The materials which I have found best adapted for the strips h2 of the sections h It are iron or brass, or glass and mica; but other materials which possess the same characteristics may be employed. The commutator-box is secured to, but insulated from, a ring, J, which is mounted ring J is capable of turning upon said hub, and is provided with a set-screw having a handle, L, for the purpose of moving and securing the box, so that its sections h h shall occupy the proper positions to receive from the fingers G, and continuously transmit, the current of electricity induced in the revolving bobbins or coils B, and so that the insulating-strips shall be properly located.

In order to retain the outer ends of the fingers G under all circumstances in near proximity to the interior surface of the box H, to limit their movementinward and to prevent too great a rebound of said fingers during revolution, the wires M are employed, as shown in Figs. 2 and 3, the said wires, in conjunction with the interior surface of the box H, limiting the radial movement of the fingers.

In order that the extreme distance of the outer ends of the ngers G from the interior surface of the box H may be regulated at any time during the working of the device, and when said ends become worn,the wires M are secured in rings N. (Shown in Figs. l, 2, and 3.) These rings are composed of non-conducting material, are mounted on the disks F so as to turn thereon, are provided with slots n, and are adjustably secured to said disks by set-screws O, passing through said slots and into the disks F. By turning the rings N, therefore, the extreme distance of the ends of the fingers G from the interior surface of the box may be varied to secure the most desirable results.

The operation of the device is substantially as follows: The shaft D being in revolution, the commutator-box H is so set that, upon a change of polarity in the current induced in any given pair of bobbins, the free ends of the fingers G, which are connected with said bobbins, respectively, will be upon the insulatingstrips h2. In the course of a revolution each successive pair of bobbins and its connected ngers will be brought successively into the same relation to the insulating-strips h2, and consequently a continuous current will be maintained in the exterior circuit in one direction. Should a change in the speed of revolution of the bobbins, or other causes, require a change in position of the insulating-strips with reference to the fingers, the same may be readily effected by loosening the set-screw L, turning the box to the required position, and securing it in place by means of said set-screw.

As shown in the drawings, and as hereinbefore described, the eommutator-box II is constructed to be used with coils whose inner ends are connected in pairs; but a box of similar character is adapted to be used with coils which are arranged as in the Gramme method ol' connectionthat is to say, with the interior end of one connected with the exterior end of an adjacent coil, and then connected with the rods E, respectively. Ihe only necessary change in the box for this arrangement of coils would be a substitution of insulating material for the metal sections h h', and of conducting material for the insulating-strips h2, or, in other words, contracting the conducting-sections and extending theinsulating-strips to the required degree.

Although I have described the employment of wires M for preventing too great a rebound of the fingers G, yet the said wires may be dispensed with, and flaps of felt, rubber, or other proper material, M', Fig. 5, may be arranged to underlie each series of fingers and be hinged to the rods E, respectively, so as to move by centrifugal force with said ngers. The liaps for each series of iin gers being composed of a single piece, they will act as cushions for them.

The mechanism within the box may also be varied. Instead of employing' the rods E and hinged lingers G, already described, the boxes E and bars G, loosely occupying said boxes, may be substituted for the said rods and fingers, respectively, as shown in Fic. 4. The wires b would be connected with the boxes E', which would be attached to non-conducting disks F, secured to the shaft D. rIhe operation of this mechanism is substantially the same as that first described, since during the revolution of the shaft the bars G would be maintained in contact with the interior surface of the box H by centrifugal force, the outer ends ofthe bars preferably being brought to a rounded edge to reduce friction.

From the foregoing description it will be seen that the friction between the commutatorbox and the revolving series of fingers is slight, since the contact between said fingers and the box is effected simply by centrifugal force. The amount of friction, therefore, in my improved commutator is much less than in others where stationary spring-brushes are pressed against a revolving sectional cylinder.

It is also obvious that a short-circuiting of the bobbins is prevented, as no definite series of ngers is in contact with both conductingsegments of the commutator-box at the same time.

The character of my commutator particularly adapts it to preserving the lubrication of the parts, as the lubricant is collected by centrifugal force upon the interior surface of the box; and since the ends of the box are nearly closed by the disks F, but little evaporation can take place.

It will be observed that before the revolution of the shaft D absolutely ceases the iingers above a horizontal plane passing through the axis of the shaft will fall by the force of gravity, and the several currents passing through them respectively will be broken. In most cases, if not all, the entire number of currents will be broken. If, therefore, all the currents are broken when the shaft ceases to revolve, no reversal of the circuit can take place, and should one or more currents remain unbroken a reversal could only take place in such currents.

I ani aware that in electrical circuit-closers an increase in pressure between two contactsurfaces has been attained bycentrifu gal force; and I am also aware that wood, ivory, cement, and various other insulating materials which are easily worn down by friction have been employed in the construct-ion of conimntators; such, therefore, I do not claim.

Having described my inveiition,whatI claim, and desire to secure by Letters Patent, is-

l. The combination, with the armature of a magneto-electric machine, of fingers or bars connected in series with the bobbins surrounding said armature and arranged to revolve therewith, and a box or casing surrounding` said fingers and composed ot' two or more conducting and insulating sections, respectively, whose interior surfaces are concentric with the path of revolution of the fingers, and with which they are caused to make contact by centrifugal action, substantially as and for the purpose set forth.

2. The combination, with the armature of a magneto-electric machine, of fingers or bars connected in series with the bobbins surrounding said armature, arranged to revolve there with, and capable, as described, of a movement by centrifugal force from their axis of revolution, and a box or casing surrounding said fingers, adjustably mounted, so as to be turned and fixed in a proper position with reference thereto, and composed of two or more conducting and insulating sections, respectively, whose inner surfaces are concentric with the fin gers path of revolution, whereby acontinuous current of electricity is supplied to the outer circuit, substantially as set forth.

3. In acommutator for magneto-electric machines, the combination, with a box or casing composed of two or more conducting and insulatin g sections, respectively, whose inner faces form a cylindrical surface, of fingers or bars connected in series with the bobbins of the armature, mounted concentric with the interior surface of said box and capable of receding from contact with the box when not influenced by centrifugal force, substantially as and for the purpose set forth.

4. In a cominutator for magneto-electric machines, the combination, with the shaft which revolves the bobbins upon the armature, of iin gers or bars connected in series with said bobbins, and mounted on insulating-disks secured to said shaft, and capable of a movement by centrifugal force from the axis of said shaft, of a box or casing surrounding said fingers, and composed of two or more conducting and insulating sections, respectively, whose inner surfaces are concentric with said shaft, substantially as set forth.

5. In a commutator for magneto-electric machines, the combination, with a box or casing composed of two or more conducting and insulating sections, respectively, whose inner faces form a cylindrical surface, and fingers or bars connected in series with the bobbins of the armature, and mounted concentric with the interior surface of said box, and capable of being brought into contact with the box by centrifugal force, of a series of cushions underlying said fingers, substantially as and for the purposes specified.

6. In a commutator, the combination, with the disks F, rods E, fingers Gr, and box H, of the adjustable rings N and wires M, substantially as shown and described.

7 The commutator-box H, composed of two or more metal conducting-sections and a corresponding number of mica or glass sections, substantially as set forth.

JOSEPH OLMSTED.

XVitnesses:

Epson SALIsBURY J oNEs, WM. A. CADY.

IOO 

